Output variables' name which contains a certain string

Question

I want to check multiple variables if they're containing a certain string. Therefore I'm using the includes method. This is working so far.

But how do I get the name of the variable which is containing the wanted string? In the following example I need to get "categoryopt2" as the output.

This is the JSFiddle.

Code:

var categoryopt1 = '';
var categoryopt2 = "test";

if (categoryopt1.includes('test') || categoryopt2.includes('test')) {

    // in this case get "categoryopt2" as a variable: 

    var matchvariablename = "categoryopt2";

}